The Froment sign , also known colloquially as the paper strip test, is a neurological sign of paralysis of the ulnar nerve . It was named after the French internist Jules Froment (1878–1946).
The Froment's mark is tested by asking the patient to hold a sheet of paper or other flat object between thumb and forefinger in such a way that it is difficult for the examiner to pull the paper away. In the event of damage to or lesion of the ulnar nerve or paralysis of the adductor of the thumb ( adductor pollicis muscle ), a compensatory flexion of the thumb joint instead of an adduction occurs . The flexion is caused by the innervation of the long thumb flexor ( flexor pollicis longus muscle ) by the median nerve ( nervus medianus ).
If the median nerve is paralyzed at the same time, the sign is absent. A positive Froment's sign is typical of distal paralysis of the ulnar nerve below the upper arm. Common locations of the nerve lesions are the ulnar groove (sulcus ulnaris) in the area of the elbow joint and the Loge de Guyon (Guyon Lodge). The corresponding clinical pictures are called ulnar groove syndrome (sulcus ulnaris syndrome, SUS) or Loge de Guyon syndrome . In the case of ulnar paralysis along the entire length between the upper arm and wrist, the characteristic clawed hand develops as a sign of complete ulnar paralysis .
- Klaus Poeck , Werner Hacke : Neurology . 12th edition Springer-Verlag, Berlin 2006, ISBN 3-540-29997-1 , p. 641.
- Hoffmann-La Roche AG (Ed.): Roche Lexicon Medicine . 4th edition Urban & Schwarzenberg, Munich 1998, ISBN 3-541-17114-6 .